for i=
t=0:0.1:10;
x0= [i;0]
[t,x]=ode45(@dynamika,t,x0)
hold on
plot(x(:,1),x(:,2),'o-')
xlabel('theta')
ylabel('dtheta')
end

function dx = dynamika(t,x)
theta=x(1)
dtheta=x(2)
g=9.81
m=1
r=1
f=1
ddtheta= -g/r * cos(theta) - f/m * dtheta;
dx=[dtheta;...
    ddtheta];
end